Typically wax is used as a fuel in traditional candles. Traditional candles transfer heat to melt the wax around a wick via radiation. The process delivers heat slowly and inefficiently resulting in a slow rate of melting the wax around the wick and creating the melt pool. Performance candles, candles that are used to drive a volatile active ingredient into the air, rely on developing a melt pool since the rate of active delivery is dependent on the size or surface area of the pool. Traditional candles can take four or more hours to create a melt pool of sufficient size to fill a typical room or area with its volatile active ingredient.
At the same time, because the flame size is limited and the resulting heat flux generated by the flame so small, the operating temperature of a candle melt pool is barely above the melt temperature of the wax, which limits the rate and the completeness of the volatile chemical delivery and limits the pallet of active ingredients that can be functional to those that work at lower temperatures.
Because of the small flame, slow melt pool development, and low operating temperature of the melt pool, performance candles suffer from sluggish and incomplete delivery. Performance candle formulators (like perfumers) are restricted to a limited breadth of ingredients that can be effectively used.
Further, traditional candles have flame sizes that are greatly limited. Candles used indoors are limited in size and in heat of the flame due to the creation of soot as the candle/wick system increases in size. As such products move outdoors, where soot can be accommodated, larger flames become increasingly difficult to create because larger wicks become difficult to ignite. This is due to the overall mass and heat capacity of the wick and wax, which makes it difficult or impossible to vaporize the fuel for ignition.
Indoor or traditional candle type products are therefore limited in flame size and heat delivery. The indoor use of candles can be used for lighting as well as delivery of a volatile active ingredient like fragrance, medicinal ingredients, or insect repellent (if used outdoors). Unfortunately, the flame size and heat limitations of the traditional wick and wax systems result in products that create low light and take exceptionally long times for the melt pool to develop. Since the active delivery is a function of both the wax/fuel melt pool size and operating temperature, the volatile active ingredient is slow to release and to be delivered to the surroundings. Even the Glade™ Scented Oil Candle that uses metal fins within the flame takes almost an hour to create a melt pool. In the outdoor use environment, this melt pool issue is exacerbated because of cooler air temperatures or the cooling effects of breezes.
Outdoor products rely on more flammable fuels like mineral oils or alcohols. Alcohol fuels like ethanol, isopropyl alcohol, and other short chain alcohols have recently been recalled due to their extreme flammability and ability to carry the fire without a wick. Mineral oil type fuels, like those used in yard torches, are acutely toxic to the respiratory system upon even the slightest ingestion. In addition, the liquid fuels are prone to creating excessive soot and develop and deliver an oil refinery off odor.
The present inventor has recognized that waxes, including but not limited to paraffin, soy wax, palm wax, beeswax, and others, would make ideal fuels, especially for outdoor products that desire and require larger flames. Additionally, the present inventor has recognized that indoor applications could benefit from both light intensity improvements as well as faster wax pool development. The present inventor recognizes the need for a device that allows for faster wax pool melting and increased heat production.
Further, wicks or wick material often function as a filter and, like filters, are prone to fouling or clogging resulting from prolonged use or use with “dirty” filtrate (or fuel in the case of wicks). Most wicks are consumable and are not plagued by fouling or clogging; yet the phenomenon presents itself and can be dangerous as carbon pills form at the end of consumable wicks.
The present inventor has recognized that the benefits of a reusable or permanent wick are many and varied and include, but are not limited to, flame control, flame staging, and, in some applications, creating flames of unique geometry, hotter flames, larger stable flames, and less soot. However, reusable wicks are prone to clogging or fouling by the fuel used—especially fuels that contain higher levels of longer chain hydrocarbons (products like waxes or paraffin). These kinds of fuel with repeated use can lead to build-up of varnish, tar, carbon deposits, and other materials that can prevent the liquid fuel from flowing through the wick material, which results in diminished performance (smaller flames) and ultimately complete failure. In effect, the chemical nature of hydrocarbon fuels and their natural inclusion of longer chain components (even at very low levels) has heretofore made using permanent or reusable wicks difficult or practically impossible.
The present inventor has recognized the need for a device that allows reusable or permanent wicks while diminishing or eliminating the cumulative effects of fouling or clogging caused by hydrocarbon fuels.
Moreover, the present inventor has recognized that unlike traditional candles with a consumable wick, reusable and permanent wick candles offer the user the option to make larger and more stable flames, to create wax burners that shed more light, to create candles that produce larger and warmer melt pools that in turn more effectively deliver a volatile ingredient to the environment, and to repeatedly operate the system with no waste.
However, since the reusable or permanent wick remains with the burner apparatus, consideration is needed for preparing the wick for reuse. The present inventor has recognized that when the wick is barren of any fuel, it may require priming. The present inventor has recognized that priming must be enough to allow easy ignition without taking too long to ignite or without flooding the point of ignition. Then that first ignition point must provide enough heat to the surrounding wax to stoke the developing flame without melting so much wax that the melted wax restricts or even douses the developing flame. The present inventor has recognized that an imbalance of both the priming and stoking stages of the developing flame can result in starving the flame or in partially or completely flooding the first ignition.
The present inventor has recognized the need for a solid fuel, such as solid wax structure that repeatedly and reliably offers a natural priming location for wick ignition and then automatically manages the stoking stage to allow uninhibited and full development of the desired flame. Further, the present inventor recognized the need for a device that provides a main wax portion that is to be melted by the flame and used through complete melt and combustion.
The present inventor recognized that some permanent wicks can be hard to ignite, especially as the cumulative ignitions or uses increases above 20 to 40 ignitions. Often times, the time to ignite can reach in excess of 40 seconds. This makes a reusable wick difficult to ignite with a lighter and very difficult or impossible to ignite with matches. One way to make it easier to ignite is to expose more wick. However, this makes the resulting flame too tall and often prone to generating soot. Therefore there is a trade-off between ease of ignition and size, safety, and suitability of the flame. While larger flames may be accommodated for outdoor products like a torch or fire pot, the large flame and propensity to soot is unacceptable for indoor applications.
The present inventor recognized the need for a system that reduces both the time to ignition as well as the operating flame height of the resulting flame. Further, the present inventor recognized the need for the reduction in ignition time and flame height to be maintained and/or not to be deteriorated or significantly altered through successive uses, such as in some case above 20 or above 50 ignitions.
Certain candles are composed of a wax mass within which a cotton or other consumable material wick passes through the wax mass and exposing the uppermost portion of the wick for ignition. The wick used in such candles is typically pre-primed with wax to enable the first ignition. The art of candle making has, over thousands of years, been focused on perfecting the delicate balance of the wax fuel and the consumable wick. Once lit the wick delivers the melted wax to the flame and, as the fuel is used, the wick burns off (often causing wisps of soot) and the flame travels down to meet the fuel. A candle, however, requires an external ignition source, which is typically a match or a lighter. Because of this, a candle is prone to several inconveniences and dangers including but not limited to (1) burn hazards, especially if the wick takes too long to ignite; (2) inconvenience of not having an ignition source available to use as it may be misplaced, out of fuel, or difficult for itself to ignite; and, (3) in some cases, as in jar candles, the wick is difficult to reach and becomes dangerous to light or requires a specific or special kind of lighter (like a wand lighter), these jar style candles and other “sunk” candle designs are specially prone to burn or hot wax spilling hazards.
The present inventor recognized that it would be desirable to have a device to ignite a candle or similar wax burning assembly that is safer and more convenient. In particular, a device where the ignition mechanism or system is neither obtrusive to the flame nor obvious or visible.
The present inventor recognized that the use of a fixed position system, like a hot filament, on traditional candles will not work repeatedly since the point of ignition (the consumable wick) moves as the candle is used and the fuel is depleted. This makes the candle unable to be re-lit repeatedly and throughout the life of the candle with a fixed position system. Furthermore, the addition of any ignition system upon a traditional candle wick will obstruct the flame, be obvious or too visible, or both. Therefore, the present inventor recognized it would be desirable for a solid fuel burning system to have a reliable, convenient, and repeatable device for ignition.
Kerosene and propane heaters use a filament or piezo electric techniques to promote ignition without needing a match, lighter, or eternal flame. However, kerosene, propane, butane and other fuels that use such techniques are flammable, with fire ratings of 3 and 4, and volatile liquids or gases and require little energy to reach an ignition point. Furthermore, these fuel types are incapable of flooding or extinguishing their own flame. The use of a filament or piezo electric techniques have not been applied to candles or other wax burning assemblies previously for at least the following reasons recognized by the inventor: (1) solid wax is a non-flammable fuel, with a fire rating of 1, and, as such, imposes several thermodynamic challenges, such as: (a) the solid wax fuel must go through two phase transitions, from solid to liquid, and then from liquid to vapor, in order to ignite, (b) the solid wax fuel needs to reach a much elevated ignition temperature for ignition; (2) due to the solid wax fuel's non-flammable nature, an assembly using solid wax is prone to dowsing its own flame out with its own fuel (flooding); and (3) high temperature exposure of a filament to oxygen causes reduced life and increased frailty of the filament, making extended use difficult. The present inventor recognized a need to overcome these drawbacks and provide other benefits in a wax burning system with electric ignition.